|The experiment is simple. Put a rat in a cage, alone, with two water bottles. One is just water. The other is water laced with heroin or cocaine. Almost every time you run this experiment, the rat will become obsessed with the drugged water, and keep coming back for more and more, until it kills itself.
But in the 1970s, a professor of Psychology in Vancouver called Bruce Alexander noticed something odd about this experiment. The rat is put in the cage all alone. It has nothing to do but take the drugs. What would happen, he wondered, if we tried this differently? So Professor Alexander built Rat Park. It is a lush cage where the rats would have coloured balls and the best rat-food and tunnels to scamper down and plenty of friends: everything a rat about town could want.
In Rat Park, all the rats obviously tried both water bottles, because they didn't know what was in them. But what happened next was startling.
The rats with good lives didn't like the drugged water. They mostly shunned it, consuming less than a quarter of the drugs the isolated rats used. None of them died. While all the rats who were alone and unhappy became heavy users, none of the rats who had a happy environment did.
Professor Alexander argues this discovery is a profound challenge both to the view that addiction is a moral failing caused by too much hedonistic partying, and the view that addiction is a disease taking place in a chemically hijacked brain. In fact, he argues, addiction is an adaptation to the cage.